Airplane and control device therefor



Aug. 7, 1945. F. R. MAXWELL AIRPLANE AND CONTROL DEVICE THEREFORSheets-Sheet l Original Filed Nov. 12, 1940 Aug. 7, 1945. F. R. MAXWELL2,381,679

AIRPLANE AND CONTROL DEVICE THEREFOR Original Filed Nov. 12, 1940 2Sheets-Sheet 2 mr'wsss:

. I IZZVZXMCZZ Patented Aug. 7, 1945 Amuse AND oou'rnor. DEVIilE'rnaaaron Frank R. Maxwell, Rose Valley, Pa.

Original application November 12, 1940, Serial No. -365,347. Divided andthis applicaton March 17, 1943, Serial No. 479,433

2 Claims.

My present invention relates to airplanes and more particularly hasreference to an airplane wing having a novel slot and {lap sointerconnected that the opening, movement of the slot is under positivecontrol of the pilot at all times. More specifically, the slot is lockedin its closed position against aerodynamic forces acting on the nose ofthe wing until-the pilot moves the flap.

Numerous control deviceshave heretofore been incorporated in airplanewings to permit a high speed in flight and at the same time enable lowspeed takeofl's and permit the airplane to land in relatively smallareas. Q! course the idea of interconnecting a nose slot and a trailingedge i'iap is not novel. but to my knowledge an interconnected slot andflap combination in which the slot is positively locked against openingmovernent until the flap has begun to move has never been proposed. Thedisadvantages of having the nose slot open during certain stages offlight is believed readily apparent and any construction which willobviate such a step taking place is a real advance in the art.

An object of this invention is to provide an airplane wing with a slotand flap and the connection between the slot and flap having a lockwhich will positively prevent the slot from opening until the flapbegins to move.

Another object of this invention is to provide an airplane wing with aninterconnected slot and flap in which the slot is provided with upperand lower covers, the upper cover being locked against opening movementdue to aerodynamic forces acting on the wing until the flapbegins tomove.

Another object of the present invention is to provide a slot and flapcombination for a wing in which the connecting linkage between the slotand flap is provided with a locking device either adjacent to the slot,adjacent to the flap, or intermediate the slot and flap to prevent theaerodynamic forces acting on the nose of the.

wing from opening the slot until the flap begins to move.

And an additional object of the present invention is to provide aninterconnected slot and ilap combination for an airplane wing whereinmeans adjacent to the pilot is provided to prevent the aerodynamicforces acting on the nose of the wing from opening the slot until theflap begins tomove.

To achieve the foregoing and other objects, this invention comprisesproviding a slot adiacent to the leading edge of the wing and a ilapnear the trailing edge of the wing. The

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upper and lower openings of the slot are adapted to be closed by coverswhich conform ,to the contour of the upper and lower surfaces of thewing in their closed position. Linkage connects the flap to the uppercover and there is a connection to the lower cover which is operated bymovement of the linkage. A control extends from the operating linkage tothe cockpit or the fuselage of the airplane so that the pilot mayactuate the slot and flap by a single control.

The linkage is of such nature that the flap may move through a smallangle before the slot opens and, the aerodynamic forces working on theleading edge of the wing cannot open the upper cover until the pilot hasmoved the flap.

In the drawings:

Figure 1 is a transverse sectional view of an airplane wing equippedwith my novel nose slot and flap combination showing these parts in theclosed position.

Figure 2 is a transverse sectional view of an airplane wing equippedwith another form of my invention.

Figure 3 is a transverse sectional view of a still further form of mynovel nose slot and flap combination.

Figure 4 is a transverse sectional view of an airplane wing showing astill further form of my invention.

Figure 5 is a sectional view taken along the line t5 of Figure 4 lookingin the direction of the arrows.

Figure 6 is a side elevational view of the operating unit for moving theslot and flap shown in Figure 4.

Referring to Figure 1, l have shown an airplane wing i of any suitableconstruction having internal spars 2, a slot 3 which extends through thewing adjacent to the leading edge thereof and a flap t provided near thetrailing edge of the wing. The wing i is formed with a recess or well iiin which the flap t is pivoted as shown at t. An arm l is attached tothe flap and an operating rod 8 is pivoted to the free end of the arm las indicated at t. The rod 8 is suitably connected to the flap operatingmechanism (not illustrated) located within the cockpit or fuselage ofthe airplane.

There is also attached to the flap i a short arm Ill to which is pivotedat i i a long operating link or push rod it. As clearly shown in Figure1, the operating rod i2 extends to a point adjacent to the slot 3 and ispivoted at it to one arm of a bell crank it which is pivoted at it tothe internal structure of the wing.

, thecover I3, as shown at 2|.

The upper opening of the slot 3 is adapted to be closed by a cover l3which is hinged to the nose of the wing I. as shown at IT. A secondslot, cover I3 for the lower opening of the slot is also hinged at thepoint II. As clearly shown in the drawings, when the covers I3 and I3are in their closed positions, they conform to the contour of the upperand lower surfaces of the wing I, thereby aflording an airfoil section.

A push rod I3 is pivoted to the other arm of the bell crank I3, as shownat 23. The free end of the rod I3 is pivoted to the. undersurface of Atoggle link 22 is hinged to the lower cover I3, as shown at 22', and anelongated lever 23 is pivoted to the link 22. .The lever 23 is pivotedto the cover I3, as shown at 23, and is formed with a short oflsetportion 23. A rod 23 is pivoted to the offset portion 23, as shown at21, and the rod 23 is further formed with a lost motion slot 23 in whichis adapted to move a pin 23 carried by the bell crank I3. The rod 23 isattached to one of the internal spars by a tension spring 33.

It is thought apparent that since the pivot points 3, II and I3 are inline when the slot 3 and fiap'3 are in their closed positions, it is notpossible for the aerodynamic forces working on the leading edge of thewing to rock the bell crank I3 about its pivot I3 to cause the upperslot cover I3 to open. This is a very important feature of the presentinvention in that it will positively prevent the slot in the leadingedge of the wing from being opened except when such opening is desiredby the pilot of the airplane,

When the bell crank has rocked sufficiently to cause the push rod I3 toopen the cover I3 slightly, the offset portion 23 and the lever 23 andlink 22 will move the lower slot cover I3 into a well or recess 3|provided in the upper slot cgver I3, as shown in Figure 1. This willgive an airfoil section to the upper cover I3 and as the upper slotcover is moved further, the lower slot cover will remain in its nestedposition and thus ailord optimum airflow through the slot 3.

In Figure 2 there is covered a still further form of my invention. Inthis modification, the operating link I2 is hinged at 33 to one arm of abell crank 3| and the bell crank is pivoted at 32 to the internalstructure of the wing I. A second operating link 33 is pivoted to theother arm of the bell crank, as shown at 33. The opposite end of thelink 33 is pivoted at I3 to the bell crank I3 which operates the upperslot cover I 3.

It should be noted that when the slot 3 and the flap 3 are in the closedpositions the pivot points I3, 33 and 32 are in a straight line, therebyaffording a lock, and it is not possible for the aerodynamic forcesacting on the nose of the wing to open the upper slot cover I3. Clearly,the slot 3 can only be opened when the pilot manipulates his controls tolower the flap 3 to rock the bell crank 3| about the ivot 32.

In Figure 3, there is shown another form of slot and flap combination inwhich the mechanism holding the upper slot cover I3 in its closedposition is adjacent to the slot 3. In this form, it can be seen thatthe operating link I2 is pivoted at I3 to a lever 33 which is pivoted at3| to the internal structure of the wing I at a point adjacent to thenose. A push rod 32 is pivoted to the lever 33 as shown at 33, and tothe upper slot cover as shown at 33. The rod 32 is curved as indicatedat 33 so that it will not interfere with the pivot point 3| of the lever33.

Pivoted to the lower slot cover I3 as shown at 33 is a short rod 31.Secured to the end of the rod 31 is a sleeve 33 in which is disposed ahellcal spring 33. Pivoted at 13 to the lever 33 is a rod II whichextends into the sleeve 33.. A pin I2 provided on the rod II projectsthrough a lost motion slot 13 provided in the sleeve 33. It is thoughtobvious therefore that when the lever 33 is moved about its pivot 3| bythe lowering of the flap 3, the rod II will slide in the sleeve 33,compressing the spring 33, thereby causing the lower slot cover I3 tomove to the broken line position shown in Figure 1 whereby a smoothcontour is provided in the slot 3. 1

It should be further observed that the pivot points I3, 3I and 33 are ina substantially straight line when the slot 3 and the flap 3 are intheir closed positions. As a result, it is not possible for the upperslot cover I3 to be opened by virtue of the forces acting on the wing I.

By placing the straight line pivot points I3, 3|, 33 adjacent the slotcover I3, the relatively great aerodynamic forces tending to open theslot will be confined to this structure and not be transmitted to theother control mechanism and surfaces.

In Figure 5, it will be noted that the flap horn. 1 is pivoted at 33 tothe push rod 3. The push rod 3 in turn is pivoted at 3| to a link 32hinged at 33 to a. supporting member 33 of the wing I.

- A second link 35 is also .pivoted at 3| to the rod 3 and at 31 to anut 33. The nut 33 engages screw threads 33 provided on a shaft 33journaled at 3| in the internal structure of the wing I. A sprocket 32is provided for the shaft and a chain 33 is trained over the sprocket32. The chain also runs over a second sprocket 33 provided on a shaft 33which is rotatably mounted in the cockpit or fuselage of the plane. Theshaft 33 has formed therein a worm 33 which meshes with a segment 31also supported in the cockpit as shown at 33. An operating handle 33 isprovided for imparting movement to the shaft 33.

Attached to the segment 31, as indicated at I33,

is a rod I3I which is pivoted to arms I32 carried by a shaft I33journaled in the internal structure of the wing. Also attached to theshaft I33 are arms I33 to which is pivoted at I33 the operating link I2.

It is thought apparent that when the pilot rotates the shaft 33 by thehandle 33, the shaft 33 will be rotated and the flap 3 will be loweredby virtue of the movement of the nut 31 along the screw threads 33. Atthe same time the arm I33 will be moved rearwardly, thus pulling thelink I2 rearwardly, causing the bell crank I3 to be moved about thepivot I3, enabling the slot 3 to be opened. In view of the fact that thepoints I33, 33 and I32 are in a straight line, it is not possible forthe aerodynamical forces working on the wing to open the upper slotcover I3.

From the foregoing description, it will be appreciated that the linkageconnecting the slot and flap may be provided with a locking deviceeither near the slot, adjacent to the flap, or intermediate the slot andflap to prevent the aerodynamic forces acting on the wing from openingthe spirit of the invention, or exceeding the scope of the appendedclaims.

This application is a division of application filed by me November 12',1940, Serial No. 365,347, now Patent No. 2,321,837, granted July 15,1943.

What I claim and desire to protect by Letters Patent is:

1. An airfoil comprising a main section, a slot cover movably mountedadjacent to the leading edge of the main section and adapted to be movedto open and close a slot, mechanism for moving the slot cover to openand close the slot and a stop operative to limit the .cover closingmovement of said mechanism when the slot is fully closed, said mechanismbeing arranged to be in at least a dead center position with respect toslot opening movement of the cover when the slot is fully closed and tobe moved out of dead center position to move the cover to open the slot.

2. An airfoil comprising a main section, a slot cover movably mountedadjacent to the leading edge of the main section and adapted to be movedto open and close a slot, mechanism, including a plurality of memberspivotally connected at at least three points, for moving the slot coverto open and close the slot and a stop operative to limit the coverclosing movement of said mechanism when the slot is fully closed, saidmechanism being arranged so that three points of pivotal connectiontherein will be in line placing the mechanism on dead center withrespect to slot opening movement of the cover when the slot is fullyclosed and so that the said three points of pivotal connection may bemoved out of line to move the cover to open the slot.

FRANK R. MAXWELL.

